Haas Technical Documentation Haas Hydraulic Power Unit - Troubleshooting Guide Scan code to get the latest version of this document Translation Available A: Haas HPU for most lathes made before 2016. B: Haas HPU for most lathes made after 2016. Note: Not all lathes will have all of the components shown. [1] Hydraulic pump [7] Pressure filter [2] Chuck and Tailstock pressure adjustment valves [8] Intake screen [3] Chuck and Tailstock pressure gauges [9] Pressure sensor [4] Oil fill cap [10] Heat exchanger (can be mounted remotely, with or without fans) [5] Oil dip stick/oil sight glass [11] Cooling fans [6] Solenoids [12] Return filter Copyright 2018 by Haas Automation, Inc. No unauthorized reproduction Last Published On November 29, 2017 1/10
Symptom Possible Cause Corrective Action The hoses are split or the fittings are loose. Tighten the fittings or replace the hoses. Oil leaks Chuck or tailstock does not operate correctly. or Incorrect chuck or tailstock clamp force or pressure. Pressure fluctuates wildly. Pump oscillates and vibrates. or Noisy Overheating Low or no hydraulic pressure. The Tailstock pressure does not adjust. Damaged pressure gauge. The oil tank overflows. Coolant contaminated the oil. The solenoid system does not operate correctly. There are air bubbles in the oil. The oil level is low. A filter is clogged. The adjustment valve is contaminated. Coolant contaminated the oil. There are air bubbles in the oil. The oil level is low. The fans do not operate. Coolant contaminated the oil. Overheating. A filter is clogged. The HPU pump needs adjustment. The oil level is low. The fans do not operate. There are air bubbles in the oil. Setting 216 is not enabled. A filter is clogged. Incorrect power phasing - the pump motor is running backward. The Tailstock Rapid Solenoid is engaged on an ST-10/15. Snubber screw has backed out. Diagnose the cause and drain the oil to the correct level. Check the coolant collector for blockage. Troubleshoot the system. Reduce the clamp force, RPM, or duty cycle. Inspect for oil leaks on the intake pipe. Re-configure the return and pick-up pipes. Fill the HPU to the correct oil level. Check the pressure filter and the intake screen for clogs. Open the adjustment valve to purge the system. Check the coolant collector for blockage. Reduce the clamp force, RPM, or duty cycle. Inspect for oil leaks on the intake pipe. Re-configure the return and pick-up pipes. Fill the HPU to the correct oil level. Make sure the fans operate. Check the coolant collector for blockage. Check for signs of overheating. Check the pressure filter and the intake screen for clogs. Contact your local Haas Factory Outlet. Refer to the Lathe - Hydraulic Power Unit - Nachi Pump Adjustment. Do not replace the pump. Fill the HPU to the correct oil level. Make sure the fans operate. Reduce the clamp force, RPM, or duty cycle. Enable Setting 216. Check the pressure filter and the intake screen for clogs. Check the phasing indicators and change the incoming power cables, if necessary. Make sure that the Tailstock Rapid solenoid is not engaged when you adjust the Tailstock pressure. Press [RESET] twice after you release [EMERGENCY STOP]. Remove the gauge, install the snubber set screw, install new gauge. Copyright 2018 by Haas Automation, Inc. No unauthorized reproduction Last Published On November 29, 2017 2/10
Symptom Possible Cause Corrective Action Copyright 2018 by Haas Automation, Inc. No unauthorized reproduction Last Published On November 29, 2017 3/10
Electrical Diagram Oil Leaks If the oil tank overflows, find the cause, and fill the oil to the correct level. If the oil is contaminated with coolant, drain and replace the oil (refer to the Coolant Contamination section). Make sure the hoses are routed correctly [4] and are secure. Tie them together with zip ties [3]. Damage can occur to the hoses if they rub [1] against other components, have sharp bends, or are kinked [2]. Replace the hoses if they are damaged. Check the condition of the hydraulic hose fittings: Look for leaks at both ends of the hose. If a leak is found, try tightening the fittings. Refer to Lathe - Hydraulic Power Unit (HPU) - Hoses and Fittings - Maintenance. If a fitting has cracks [5], wear, continues to leak, the hose must be replaced. Do not over-tighten the fittings. For hose replacement instructions, refer to Lathe - Hydraulic Power Unit (HPU) - Hoses and Fittings - Maintenance, or search for the document by keywords on diy.haascnc.com. Copyright 2018 by Haas Automation, Inc. No unauthorized reproduction Last Published On November 29, 2017 4/10
Solenoids 1. Turn off the power to the machine. 2. Remove the solenoid valve. Use compressed air to clean the solenoid valve. 3. Reinstall the solenoid valve. Caution: Do not lose the (4) o-ring when you reinstall the solenoid valve. 4. Test for correct operation. It is normal for the solenoids to be hot to the touch. Check the voltage to the solenoid. 1. Pull the solenoid connectors partially apart so you can access the leads with your needle-tip probes while the solenoid is connected. 2. With the chuck or tailstock in operation, measure the voltage to the solenoid. The measured voltage must be 120 VAC. If there is no voltage, go to I/O PCB - Troubleshooting Guide (Classic Haas Control) to troubleshoot the I/O PCB. If the solenoid receives voltage, but it does not operate correctly, clean the valve: Settings Make sure Setting 216 SERVO AND HYDRAULIC SHUTOFF is set to (120) seconds or less. Do not have this setting set to (0), the HPU will not turn off, and will create unwanted air bubbles and heat. This setting will power-down the HPU when the machine is idle. This helps dissipate the air bubbles in the oil. Machines with the Classic Haas Control with software version 11.27A or higher and all Next Generation Control machines do not allow you to set this setting to (0). The limits on this setting for these machines are 10 seconds to 99 minutes. Copyright 2018 by Haas Automation, Inc. No unauthorized reproduction Last Published On November 29, 2017 5/10
Air Leaks/Pickup Tube Check for oil leaks at the intake pipe [1]. If there are leaks, clean the threads on the intake pipe [1]. Reapply thread sealant, and install the intake pipe [1]. If the symptom persists, go to the Tank Reconfiguration section to reconfigure the pipes. Oil Pressure Always make sure the oil level is correct and the filter is clean (refer to the Oil Level section and the Filter section). Push [EMERGENCY STOP]. Wait half an hour while the air and oil separate. Resume machine operation. Check if the normal pressure returns while the operation resumes. If the symptom occurs again: Reduce the hydraulic clamp pressure by about 25 PSI to reduce the rate of the hydraulic union leak at the slip joint. Reduce the cycle time with higher feed rates. Reduce the spindle RPM. Maximum Chuck Operating Pressures Type psi Bar 5" Chuck 330 23 6" Chuck 330 23 8" Chuck, 2" Bore 330 23 8" Chuck, 2.5" Bore 260 18 10" Chuck 330 23 12" Chuck, 3" Bore 400 28 12" Chuck, 4" Bore 250 17 15" Chuck 340 23 18" Chuck 300 21 Caution: Do not add anti-foaming agents. These agents are already present in the HPU oil. Copyright 2018 by Haas Automation, Inc. No unauthorized reproduction Last Published On November 29, 2017 6/10
Oil Level Check the gauge [1] or dipstick [2] to make sure that the HPU has enough oil. If the oil level is low, check for a leak. If there is a leak, repair the leak. Refill the oil. Fans If the HPU oil overheats: Some HPU assemblies have fans installed on the back. Make sure the fans operate when the spindle is in operation. Make sure the spindle motor fan operates. If the machine has a heat exchanger, make sure the heat exchanger is clean and its fan operate correctly. Not all heat exchangers have a separate fan. Some machines have remotely-mounted heat exchangers with integral fans. The spindle fan on machines with the Classic Haas Control with software version 11.27A or higher and all Next Generation Control machines must stay on when the HPU is on. Filters Clean or replace the pressure filter [1] on the pump assembly. Make sure the intake filter [2] is not clogged. Clean it if necessary. Test the hydraulic components for the correct pressure. Copyright 2018 by Haas Automation, Inc. No unauthorized reproduction Last Published On November 29, 2017 7/10
Adjusting Valves Check the adjustment valve for debris: With the HPU powered on, open and close the adjustment valve fully to flush any contamination out. Power off the HPU and remove the adjustment valve. Inspect the o-rings for damage. Damaged o- rings can also cause incorrect pressure. If the adjustment valve is damaged, replace it. For adjustment valve replacement instructions, click the link for ST/DS Lathe - Chuck and Tailstock Pressure Adjusting Valve - Replacement, or search for the document by keywords on diy.haascnc.com. the pressure can be adjusted. An ST-10/15 can have the Rapid Tailstock solenoid engaged when the tailstock is not in use. Press [RESET] twice after you release [EMERGENCY STOP] to disengage the solenoid and Coolant Contamination Find the coolant return line under the spindle. If chips block the coolant return line, coolant floods into the hydraulic union and will contaminate the HPU oil and cause it to foam. It can also cause the tank to overfill. Unclogg the coolant return line. Drain the HPU and blow shop air through the hoses. Clean or replace all HPU filters. Clean the HPU and refill it with new oil. Cycle the chuck and tailstock several times. Check the oil again. Copyright 2018 by Haas Automation, Inc. No unauthorized reproduction Last Published On November 29, 2017 8/10
Tank Reconfiguration Reconfigure the return and pick-up pipes to separate them. This gives the oil more time to dissipate the bubbles. Remove the elbow fitting [1] from the intake line [2] and the intake filter [3]. Install the new intake screen [4] (Haas P/N 58-1832) on a new nipple (available locally). The new nipple length must be long enough so the new intake screen [4] is 1/4" from the bottom of the tank. Remove the return line [5] from the return drain [6]. Install an elbow fitting [7] between the return line [5] and the return drain [6]. Install a new pipe nipple (available locally) to the elbow fitting [7] that reaches approximately 1" from the side of the tank. Electrical Phasing The power supply PCB has a phase detect with neon indicators on the top center portion of the board. Make sure that the electrical power is phased correctly: Green Light: The incoming power is phased correctly. Orange Light: The incoming power is incorrectly phased. Both Lights: A phase is missing (there is a loose cable in the system). If the electrical power is phased incorrectly: Set the main circuit breaker to the OFF position. Lock the main circuit breaker. Use an approved lock with an approved safety tag. Swap the #74 and #75 incoming power cables at the main transformer. Damaged Gauges Copyright 2018 by Haas Automation, Inc. No unauthorized reproduction Last Published On November 29, 2017 9/10
Damaged gauges may include: Displaying incorrect pressure, broken needles, not returning to 0 PSI when off, ect. Remove the pressure gauge and check that the snubber set screw [1] has not backed out. The snubber set screw is similar to the Haas Liquid Grease restrictor fitting. Re-install the snubber set screw without any thread locker. Replace the gauge as needed. Copyright 2018 by Haas Automation, Inc. No unauthorized reproduction Last Published On November 29, 2017 10/10